Biomarkers, Tumor, Child, Child, Preschool, ELAV Proteins, ELAV-Like Protein 2, ELAV-Like Protein 4, Female, Gene Expression Regulation, Neoplastic, Humans, Infant, Infant, Newborn, Male, Multigene Family, Neoplasm Proteins, Nerve Tissue Proteins, Neuroblastoma, Neurons, Prognosis, RNA, Messenger, RNA, Neoplasm, RNA-Binding Proteins, Single-Blind Method, Survival Analysis, Tumor Cells, Cultured